(1) Preliminary studies have shown that inhibition of cells in striate cortex can be evoked by stimulation of the non-dominant eye in animals subjected to alternating eye occlusion in the first few months of life. Inhibition via the non-dominant eye will also be studied in animals binocularly deprived, or masked without deprivation. Studies will be addressed to the orientation-selectivity of inhibitory effects, its columnar organization, and the detailed structure of inhibitory receptive fields. (2) During hours when the principal investigator is sleeping, the same animals will be used to study the relation between direction selectivity and contour length or texture of a stimulus array (a control needed for the interpretation of published experiments on the relation between directional selectivity and stimulus length). (3) Attempts will be made to stain with Procion dye some of the few cells driven by a monocularly deprived eye. (4) A mathematical model of cortical development that predicted the preliminary findings mentioned above will be published, and extensions to the problems of the influence of neonatal experience on selectivity for orientation and direction of movement will be pursued.